There will be taken blood samples of the participants including potassium, sodium, creatinine, fasting glucose, hemoglobin A1c, albumin, calcium, 25-OH vitamin D, PTH, β-carotene, vitamin A (retinol), vitamin K (phytomenadione), pp, copper, zinc and selenium, iron, hemoglobin, ferritin, leukocytes, liver count, and blood and urine investigation of bone turnover. In addition, patients will be DXA scanned for assessment of bone mineral content and composition.